Document Detail


Divergence involving global regulatory gene mutations in an Escherichia coli population evolving under phosphate limitation.
MedLine Citation:
PMID:  20639316     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Many of the important changes in evolution are regulatory in nature. Sequenced bacterial genomes point to flexibility in regulatory circuits but we do not know how regulation is remodeled in evolving bacteria. Here, we study the regulatory changes that emerge in populations evolving under controlled conditions during experimental evolution of Escherichia coli in a phosphate-limited chemostat culture. Genomes were sequenced from five clones with different combinations of phenotypic properties that coexisted in a population after 37 days. Each of the distinct isolates contained a different mutation in 1 of 3 highly pleiotropic regulatory genes (hfq, spoT, or rpoS). The mutations resulted in dissimilar proteomic changes, consistent with the documented effects of hfq, spoT, and rpoS mutations. The different mutations do share a common benefit, however, in that the mutations each redirect cellular resources away from stress responses that are redundant in a constant selection environment. The hfq mutation lowers several individual stress responses as well the small RNA-dependent activation of rpoS translation and hence general stress resistance. The spoT mutation reduces ppGpp levels, decreasing the stringent response as well as rpoS expression. The mutations in and upstream of rpoS resulted in partial or complete loss of general stress resistance. Our observations suggest that the degeneracy at the core of bacterial stress regulation provides alternative solutions to a common evolutionary challenge. These results can explain phenotypic divergence in a constant environment and also how evolutionary jumps and adaptive radiations involve altered gene regulation.
Authors:
Lei Wang; Beny Spira; Zhemin Zhou; Lu Feng; Ram P Maharjan; Xiaomin Li; Fangfang Li; Christopher McKenzie; Peter R Reeves; Thomas Ferenci
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Publication Detail:
Type:  Letter; Research Support, Non-U.S. Gov't     Date:  2010-07-16
Journal Detail:
Title:  Genome biology and evolution     Volume:  2     ISSN:  1759-6653     ISO Abbreviation:  Genome Biol Evol     Publication Date:  2010  
Date Detail:
Created Date:  2010-07-19     Completed Date:  2010-12-06     Revised Date:  2012-04-23    
Medline Journal Info:
Nlm Unique ID:  101509707     Medline TA:  Genome Biol Evol     Country:  England    
Other Details:
Languages:  eng     Pagination:  478-87     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Bacterial Proteins / genetics
Directed Molecular Evolution*
Escherichia coli / genetics*,  metabolism*
Escherichia coli Proteins / genetics
Genes, Bacterial
Guanosine Tetraphosphate / metabolism
Host Factor 1 Protein / genetics
Models, Genetic
Mutation*
Phenotype
Phosphates / metabolism*
Proteome
Pyrophosphatases / genetics
Sigma Factor / genetics
Stress, Physiological
Chemical
Reg. No./Substance:
0/Bacterial Proteins; 0/Escherichia coli Proteins; 0/Hfq protein, E coli; 0/Host Factor 1 Protein; 0/Phosphates; 0/Proteome; 0/Sigma Factor; 0/sigma factor KatF protein, Bacteria; 33503-72-9/Guanosine Tetraphosphate; EC 3.1.7.2/guanosine-3',5'-bis(diphosphate) 3'-pyrophosphatase; EC 3.6.1.-/Pyrophosphatases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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